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( No Model.)

G. M. WEIRICH. DENTAL IMPRESSION'GUP. No. 415,594. Patented Nov. 19, 1889.

N. PETER$ Phulo-Llthogrzpher. Washinglnm 0.0

UNITED STATES PATENT OFFICE.

GEORGE M. \VEIRIOII, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HENRY D. JUSTI, OF SAME PLACE.

DENTAL lMPRESSlON-CUP.

SPECIFICATION forming part of Letters Patent No. 415,594, dated November 19, 1889.

Application filed April 29, 1889. Serial No. 308,971. (No model.) I

To all whom it may concern.-

Be it known that I, GEORGE M. IVEIRICH, a citizen of the United States, residing in the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvement in Dental Impression Cups or Trays, which improvement is fullv set forth in the following specification and accompanying drawings.

My invention consists of a dental impression cup or tray having an elastic or flexible edge or rim connected therewith, as hereinafter described and claimed, whereby the same yields to the pressure when the impression is withdrawn from the mouth, and then returns to its normal position, forvpurposes hereinafter explained.

Figures 1 and 3 represent perspective views of dental impression cups or trays embodyinc my invention. Figs. 2 and 4 represent sections thereof on lines, respectively, 00 9c and y y, Figs. 1 and 3.

Similar letters of reference indicate corre sponding parts in the several figures.

Referring to the drawings, A designates a dental impression cup or tray, and B designates the edge or rim thereof, the body of the cup or tray being formed of metal, porcelain, or other material, as usual in such cases, and said edge or rim being formed of flexible or elastic material, preferably vulcanized rubber, the edge or rim being secured to the body by inserting the same in a groove or channel formed on the face of the cup and properly fastening it in said place.

It is well known that when an impression is formed of rigid or inflexible material and the plaster set, on the removal of the cup or tray from the mouth the plaster breaks at the rim, owing to the pressure exerted thereon during the removal, thus causing the dentist much annoyance and trouble in efforts to replace the broken pieces, so as to get even an approximately-correctmodel of the jaw. This is remedied by forming the edge or rim of the cup or tray elastic or flexible, whereby it yields during the removal from the mouth, so that the edge or rim may be returned or restored to its normal condition, carrying with it the pieces of plaster that may have been cracked or broken, so that the plaster impression is in great measure preserved.

In order to cause the plaster to adhere to.

the edge or rim, the latter is perforated or roughened, so that the plaster enters the openings or depressions, and thus takes better hold of the edge or rim.

I am aware that some dental impressioncnps have their bases and rims formed entirely of elastic material, and others both of metal and elastic material, the rims in the latter case being connected by means of studs or pins on the bases; but in my invention there is a continuous groove or channel in the base or body, and the elastic rim enters said groove and is applicable at either end thereof, it being securely held in place at all points along its length, and does not materially change the nature of the base or body.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is'

A dental impression-cup having a body with a groove extending near the edge from end to end thereof, and an elastic rim which is fitted in said groove said parts being combined substantially as described.

GEORGE M. WEIRICH. \Vitnesses:

JOHN A. WIEDERSHEIM, A. P. JENNINGS. 

